Long Term Evolution (LTE) uses Orthogonal Frequency Division Multiplexing (OFDM) in a downlink and Discrete Fourier Transform (DFT)-spread OFDM in an uplink. The basic LTE downlink physical resource can thus be seen as a time-frequency grid as illustrated in FIG. 1, where each resource element corresponds to one OFDM subcarrier during one OFDM symbol interval.
In a time domain, LTE downlink transmissions are organized into radio frames of 10 ms, as shown in FIG. 2, each radio frame consisting of ten equally-sized subframes of length Tsubframe=1 ms.
Internet of Things (IoT) and the related concept of Machine-Type Communication (MTC) are important revenue streams for operators and have huge potential from an operator perspective. It is efficient for operators to be able to serve MTC User Equipments (UEs) using already deployed radio access technology. Therefore, 3rd Generation Partnership Project (3GPP) LTE has been investigated as a competitive radio access technology for efficient support of MTC. Lowering the cost of MTC UEs is an important enabler for implementation of the IoT. Many MTC applications will require low operational UE power consumption and are expected to communicate with infrequent bursty transmissions and small-size data packets. In addition, there is a substantial market for Machine-to-Machine (M2M) use cases of devices deployed deep inside buildings which would require coverage enhancement in comparison to a defined LTE cell coverage footprint.
3GPP LTE Rel-12 has defined a UE power saving mode allowing long battery lifetime and a new UE category allowing reduced modem complexity. In Rel-13, further MTC work is expected to further reduce UE cost and provide coverage enhancement. The key element to enable cost reduction is to introduce reduced UE bandwidth of 1.4 MHz in downlink and uplink within any system bandwidth. As such, systems and methods are needed for determining Channel State Information (CSI) reference resources and Channel Quality Indicator (CQI) reporting for MTC operation when the UE is limited to only 1.4 MHz of bandwidth.